Scanning device

ABSTRACT

A scanning device for focusing a beam of rays in defined regions of a defined volume, comprising an input optics wherein the beam of rays penetrates first, having at least one first optical element; a focusing optics for focusing the beam of rays exiting from the input optics; and a deflecting device arranged between the first optical element and the focusing optics, for deflecting the beam of rays after it has passed through the first optical element, based on a position of the focus to be adjusted in lateral direction. In order to adjust the position of the focus of the beam of rays in the direction of the beam of rays, and optical element of the input optics can be displaced relative to the deflecting device.

RELATED APPLICATIONS

This application is a continuation of Application No. 14/209,464, filedMar. 13, 2014, entitled “Scanning Device”, now U.S. Pat. No. 9,261,697,issued Feb. 16, 2016, which is a continuation of application Ser. No.11/579,791, filed Nov. 7, 2006, entitled “Scan Device”, now U.S. Pat.No. 8,702,770, issued Apr. 22, 2014, which is a National Phase entry ofPCT Application PCT/EP06/02150, filed Mar. 9, 2006, which claimspriority to German Application No. 10 2005 013 9493, filed Mar. 26,2005, each of which is hereby fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention concerns a scanning device for focusing a luminousbeam in given ranges of a given volume, as well as a procedure forfocusing a luminous beam into given ranges of a volume.

BACKGROUND OF THE INVENTION

The focusing of a luminous beam into different given ranges of a volume,this is both in a lateral and/or transversal direction to the luminousbeam as well as in a parallel direction to the luminous beam, whichplays an important role in a series of optical devices and/or with a setof optical procedures. From now on, as luminous beams must be conceivedin particular laser beams delivered by a laser.

For example, laser beams are used in ophthalmology, in order to correctdefective vision of a human eye by a laser-surgical intervention overthe cornea of the eye. A special importance has the well-known procedureknown as “LASIK” (laser in situ keratomileusis), in which by means of apulsed laser beam material is removed not from the surface of thecornea, but from inside the cornea. This way, an external surface areaof the cornea forms a fold-like cover also known as a “flap”, whosethickness is substantially smaller than the one of the cornea. Thiscover is folded away for the actual removal treatment, whereupon a givenamount of material is removed through the area of the opened region bymeans of a pulsed laser beam, with which the defective vision iscorrected. Afterwards the cover is folded back on the opened surface.

In order to be able to cut the cover in the cornea to the exact defineddepth as carefully and precisely as possible, femtosecond laser pulsesmay be used—this is, laser pulses with suggested pulse-widths lower than10⁻¹² s. By means of such pulses, optical openings—which are alsodenominated “photo-disruptions”, which are locally limited and show anexpansion of only a few micrometers—can be produced in the cornea. Byplacing several of these optical openings very close in exact givenplaces, the cover can be formed very accurately. Thereby, a fundamentalcondition for the exact formation of the cover is the accuratepositioning of the focus of the used pulsed laser beam, not only in thelateral direction, but most of all also in the depth of the cornea andthus in the propagation direction of the laser beam.

US 2003/0053219 A1 describes a zoom lens system which is intended forsurgical applications. A zoom lens is moved in the direction of thelaser beam for focusing into different depths, whereby the focal lengthof the focusing optics is modified. In order to be able to place thefocus in the depth with the required accuracy, the zoom lens must beadjusted with a very high accuracy, which requires accordingly complexmechanics.

U.S. Pat. No. 6,751,033 B2 shows an ophthalmologic laser system, inwhich a laser beam delivered by a laser source is diverted in a lateraldirection and thereafter is focused in a given depth by using opticswith variable focal length. The same disadvantages of the systemdescribed in US 2003/0053219 A1 can be expected with this system.

A further application area for scanning devices of the above mentionedtype are those denominated confocal laser scanning microscopes, in whicha laser beam is focused on a given range of the volume of the object tobe examined. The light emitted from this area is aimed over a detectorin which a fine aperture is located over an intermediate image plane,which basically only allows the light emitted from the range and/orfocus to pass, fading out the light from neighboring regions so that adissolving takes place in the lateral and depth directions. Athree-dimensional volume of the object which is being examined can beshown by the relative motion between specimen and focus in lateraldirection and in the direction of the laser beam. The specimen tablewhich holds the object is moved by positioning the focus in thedirection of the laser beam relative to the object, is also mechanicallycomplex and due to the relatively large mass of the sample table, doesnot allow a very fast adjustment.

The basic purpose of the concerned invention is to create a scanningdevice for focusing a luminous beam into determined ranges of a givenvolume by means of a simple laser beam, in a simple and exact way in thelateral direction and in the direction of the laser beam into differentspecific ranges of a volume, that can be focused following a determinedprocedure.

SUMMARY OF THE INVENTION

This purpose will be achieved by means of a scanning device for focusinga luminous beam into determined ranges of a given volume with a set ofentrance optics, which the luminous beam enters first and which shows atleast a first optical element and a focusing optics set, by means ofwhich the luminous beam emitted by the entrance optics can be focused,and a deflecting device located between the first optical element andthe focusing optics which will deflect the luminous beam in a lateraldirection after passing through the first optical element depending onthe focus position, so it can pass through or be reflected, and wherebyat least one optical element of the entrance optics set can be movedrelative to the deflecting device in the direction of the luminous beam,in order to adjust the focus position of the luminous beam.

The scanning device also adjusts in the direction of the luminousbeam—which can be emitted from an optical radiation source such as alaser—in the direction of the entrance optics, which subordinate thedeflecting device and finally the focusing optics. The entrance opticsand the focusing optics cooperate in order to displace the focusposition of the luminous beam in the direction of the luminous beam,whereby an optical element of the entrance optics, which can be inparticular also the first optical element of the entrance optics, can bemoved in the direction of the luminous beam relatively to the deflectingdevice and/or to the focusing optics, depending on the desired positionof the focus.

The movement of the focus in lateral direction, for example transverseto the direction of the luminous beam, takes place via the deflectingdevice, which can be controlled in such a way by the control signalswhich are supplied for example by a suitable control device, that thefocus can be moved in the lateral direction into a position eitherdesired and/or determined by the control signals.

By placing the deflecting device between the first optical element—whichpreferably but not necessarily, can be in the beam direction of thefirst element of the entrance optics—and the focusing optics, therequirements of the entire optical system can be reduced since theentrance optics must only be placed for the beam near to the axis. Thissimplifies the correction and reduces the size of the elements. On theother hand, the focusing optics can be laid out in a simple way, sincefocusing takes place via the movement of an optical element of theentrance optics.

Altogether, a fast and simple adjustment of the three-dimensional focusposition in the given volume can be achieved.

The divergence of the luminous beam emitted from the entrance optics ispreferably modified by moving the displaceable optical element relativeto the deflecting device. Such a configuration of the entrance opticshas the advantage that the entrance optics can be built very simply. Thefocusing optics then focuses the luminous beam emitted from the entranceoptics depending on its divergence angle on different depths—this ispositions in the direction of the luminous beam in which a movement ofthe focusing optics is not necessary. Therefore the purpose of theinvention is also further solved by a procedure for focusing a luminousbeam into determined ranges of a volume, in which depending on theposition of the corresponding regions, the divergence of the luminousbeam is changed, and the luminous beam is transversally deflected to itsdirection of propagation and then focused. By changing the divergence ofthe luminous beam, it must be conceived that the convergence and/ordivergence angle of the luminous beam will change, and that the luminousbeams emitted by the scanning device can be convergent, divergent orpreferably parallel. After changing the divergence and before thedeflecting device, depending on the desired position of the focus, theycan be divergent, parallel or convergent. The entrance optics andfocusing optics are particularly and preferably laid out in such a wayand arranged relatively to each other that a parallel luminous beam istransferred by the entrance optics again into a parallel luminous beam,if the focus is placed in the middle of the depth region of thepredetermined volume. This has the advantage that it is possible to makecorrections of the system, with which the aberrations with small focuspenetration in the volume and the aberrations with large penetration canbe mediated.

The first optical element of the entrance optics can be for example alens, a reflective element such as a mirror, in particular a curvedmirror or a hollow mirror, or a diffractive optical element. The opticalelement which can move relative to the deflecting device can be forexample a lens. In another preferred application form, the movableoptical element is a diffractive optical element that moves relative tothe deflecting device.

Alternatively, it is preferred that the movable optical element thatmoves relative to the deflecting device is a reflective optical element.

In principle, the entrance optics can still show further opticalelements beside the first optical element. The entrance optics mayinclude a lens or a group of lenses with negative refraction power and aone of these lenses or group of lenses with positive refraction powermay be arranged downstream in the direction of the luminous beam. Suchan arrangement is characterized in a favorable way by a particularlycompact structure, and contrary to an expander with two positiverefraction power elements, shows no real intermediate image. The firstoptical element of the entrance optics can be in particular the negativerefraction power lens or the first lens of the negative refraction powergroup of lenses. The lenses or groups of lenses can thereby be arrangedin such a way that the entrance optics represents at least an expanderfor the position of the movable optical element that moves relative tothe deflecting device, and by which the cross section of a parallel,incident luminous beam can be changed, especially increased. Such anarrangement is characterized in favorable way by a particularly compactstructure.

In other implementation forms, instead of the negative refraction powerlens or group of lenses and/or the positive refraction power lens orgroup of lenses, a similarly working diffractive optical element (DOE)and/or a group of diffractive optical elements or an similarly workingreflective optical element and/or group of reflective optical elementscan be used. The lenses or groups of lenses can be thus partially orcompletely replaced by diffractive optical elements or mirrors. Thedesired function of the divergence change is then achieved with otherelements. Therefore in another application, a set of entrance opticswith a first diffractive optical element arranged in the beam directionand a second diffractive optical element arranged in the beam directioncan be used. In a basic arrangement, the first diffractive opticalelement transforms a parallel beam into a convergent beam, and thesecond diffractive optical element transforms the convergent beam againinto a parallel beam, whereby as a result of the correspondingconstruction and arrangement of the diffractive optical elements, thebeam expansion increases. By changing the divergence of the beam emittedfrom the entrance optics, the distance between the first and seconddiffractive optical elements is changed. As a further application, anentrance optics set with two concave mirrors is mentioned. The firstconcave mirror in the rays' path creates a real intermediate image,which is projected by the second mirror located in the path of rays fromthe first hollow mirror to infinity. The divergence is changed bychanging the distance between the two concave mirrors. The focal lengthratio determines the relationship between the diameter of the emittedbeam and the diameter of the incoming beam. Also combinations of lenses,diffractive optical elements and mirrors can be used.

Preferably the optical element movable relative to the deflecting deviceis a negative refractive power lens or a negative refractive power groupof lenses. In this case, the entrance optics set a particularly smallnumber of components. In particular, the first optical element of theentrance optics can be movable relative to the optical element of thedeflecting device. This entrance optics structure makes it possible onone hand to build the negative refraction power lens and the movableoptical element with very small dimensions, which in consequence due toits small dimensions can move very fast. On the other hand, aparticularly favorable speed ratio between the movement of the negativerefraction power lens and the corresponding movement of the focusresults in the direction of the luminous beam, this is that with anappropriate dimensioning of the entrance optics and the focusing optics,the movement of the negative refraction power lens entails asubstantially smaller corresponding depth movement of the focus around agiven distance, so that the accuracy requirements of a drive for thenegative refraction power lens based on achieving a given precision ofthe adjustment of the focus position in the depth are relatively small.

In order to make possible a controlled movement of the movable opticalelement relative to the deflecting device, it may be mounted on amovable mounting plate parallel to the path of rays.

Preferably the scanning device must include a driving device for therelative movement of the movable optical element of the deflectingdevice. This can have, aside from the corresponding support of themovable optical element, yet another actuator which converts controlsignals from the corresponding motion. Some examples of this actuatorcan be a piezoactuator, an electrical linear motor or also an electricmotor, whose rotational motion is converted into linear motion by atransmission, such as an eccentric cam drive so it can be used asactuator. When using electric motors, stepper motors may be used, whichhave the advantage that their movement can also be precisely controlledwithout regulation. Otherwise, the driving device can have an automaticcontrol loop, which besides the actuator can also include a sensor fordetecting the position of the movable optical element relative to thedeflecting device and a controlling circuit, which controls the actuatordepending on the position of the optical element detected by the sensor,so it can be moved to a determined target position.

The deflecting device can be in principle placed in any position betweenthe first optical element of the entrance optics and the focusingoptics. However, it is preferred that the deflecting device is arrangedbetween the entrance optics and the focusing optics. This arrangementhas the advantage that the entrance optics can be simply developed,since the luminous beam is not then moved in the entrance optics inlateral direction, if the luminous beam is moved by the deflectingdevice in a lateral direction.

The deflecting device can be in principle built in a well-known way. Forexample, it can work used for emitting the luminous beam over areflective element, such as a mirror, in two different perpendicularaxles, tiltable between each other, in which the deflecting device hasat least one further actuator, by means of which the reflective elementis tiltable around the two axes depending on the control signals. Thisapplication form has the advantage that only one reflective element isneeded.

However, the deflecting device preferably may include two movablereflective elements separated from each other and from the focusingoptics. Such a structure permits a very exact support and adjustment ofthe reflective elements and thus of the position of the focus in thelateral direction, this is in a transverse direction to the luminousbeam close to its focus. The deflecting device can have in this case twofurther actuators, which convert in each case the control signalsdepending on the desired lateral diversion and/or position of the focusduring the movement of the corresponding reflective element. Inparticular, the reflective elements for emitting the luminous beam aretiltable around axles, which are perpendicular to each other. At leastone of the reflective elements can be a mirror.

The pupil optics may be arranged between the reflective elements, whichimage the first reflective element on the second reflective element.This arrangement has the advantage that a clear pupil position results,which in a particular case can be the reflective element that theluminous beam meets first and that works as a pupil. A clear and fixedposition of the pupil is in fastidious—this is, very preciselyworking—optical systems a condition for a good correction.

In order to adjust the depth of the focus, this is in the direction ofthe luminous beam, the movable optical element designed according to theinvention may move relative to the deflecting device. This does notexclude that the focusing optics have an adjustable focal length. It ishowever preferred that the focusing optics show a fixed focal length. Inparticular this does not include any zoom lens. With the procedureaccording to invention it is preferred that focusing optics with a fixedfocal length is used for focusing the diverted luminous beam. Thefocusing optics is preferably arranged fixed relative to the deflectingdevice. With this application form the adjustment of the focus positionis not made by changing the focusing optics, which has the advantagethat this can be particularly simply laid out.

Preferably a beam splitter is arranged in the path of rays between thedeflecting device and at least one emission lens or emission lensesgroup of the focusing optics. The focusing optics lens or group oflenses are located under the emission lens or emission lenses group ofthe focusing optics, from which the luminous beam is emitted into thevolume on which it is to be focused. The beam splitter is therebypreferably arranged in such a way, that on one hand the luminous beamsdiverted from the deflecting device, fall on the emission lens or groupof lenses, and on the other hand at least one part of an observationluminous beam from the path of rays between the deflecting device andthe emission lens or emission lenses group, coming from the volume, isdecoupled. Depending upon the wavelength of the radiation of thefocusable scanning device luminous beam, the beam splitter can be laidout dichroitic, so that it affects the luminous beam and the observationluminous beam differently. Such scanning device has the advantage thatthe volume can be simply observed during the emission of the luminousbeam using at least a part of the observation luminous beam coming fromthe volume. In particular, in the case that the focusing optics shows afixed focal length and is arranged fixed and relative to the deflectingdevice, the volume can be observed independently of the focus positionof the luminous beam with fixed adjusted optics or camera.

Preferably the emission lens or the emission lenses group is adjusted insuch a way that a parallel luminous beam is focused into the givenvolume. The emission lens or emission lenses group can be conceived thenas an objective lens or objective lenses group. Thereby preferably theemission lens or emission lenses group is laid out such that the entirevolume is essentially imaged sharply to infinity, so that for monitoringthe depth of field is so large that the entire volume can be shown andobserved sharply without having to adjust the observation optics.

The focusing optics can be divided into partial optics. Preferably thefocusing optics has an entrance objective for the production of a realintermediate image from the luminous beam delivering radiation source.The focusing optics can then preferably exhibit still another tubularoptics, which images the intermediate image into the infinite. Theintermediate image formed from the tubular optics infinity is thenfocused from the emission lens or group of lenses and/or emission opticsinto the target volume. The focusing optics can be more simply correctedby this multipart arrangement. Therefore compensation effects can beused between the different parts of the focusing optics and the tubularoptics, for example the entrance objective. The partial optics can havelarger focal lengths than the focusing optics altogether. Thus forexample the ratio between the diameter of the incoming beam and thefocal length of the entrance objective can be favorably arranged,facilitating the correction. Beyond that, a possible interface resultsfor monitoring the parallel path of rays between the tubular optics andthe emission optics. In particular the focal length of the emission lensor emission lenses group can be selected in such a way that monitoringis possible simply.

The scanning device can be used for an optical radiation sources,however preferably for lasers. In particular in this case it ispreferred, that all real intermediate pictures emitted from the luminousbeam radiation source are formed in a gaseous environment, in particularair or vacuum. This has the advantage that with the use of the scanningdevice, very high intensity laser radiations are not used in the opticalopenings in the optical components of the scanning device, such aslenses or mirrors, since it could damage them.

Preferably the entrance and focusing optics are chromatically correctedover the spectral range of selected femtosecond pulses that can befocused by passing through femtosecond pulses with a dispersion inducedtemporal broadening of less than about 30%. Preferably the entireoptical system of the scanning device is corrected this way. The pulseduration can be obtained in the focus by an adapted dispersionmanagement before the pulse enters the system and the already mentionedchromatic correction of the entire optical system, which is appropriatefor less than 30% over the theoretically attainable pulse duration.Preferably this chromatic correction is appropriate for femtosecondpulses with wavelengths in a range of approx. 1040 nm. Such a scanningdevice is therefore suitable in particular for laser-surgical systems,which are meant for using femtosecond pulses for the formation of acornea flap during a LASIK treatment.

Beyond that, the optical system is preferably corrected by limiteddiffraction, so that for example the aberration caused by the optics inthe lateral direction is suppressed to a large extent and/or is reducedto a minimum.

The focusing optics is preferably regulated by an adjustment of at least0.35. In particular during the use of the scanning device forlaser-surgical purposes, it is preferred that the mobile optical elementmove relative to the deflecting device over a range sufficiently largethat the focus of the luminous beam in the beam direction moves in arange larger than 0.5 mm. Such an adjustment has the advantage that whenusing the scanning device for a LASIK treatment, a cornea flap can besimply formed without movement of the cornea relative to the scanningdevice.

For the same purpose it is preferred that the deflecting device isadjusted in such a way that the focus of the luminous beam can movealong the given volume in a lateral range with a diameter of about 11mm. This again has the advantage that the necessary cornea covers can beformed with no movement of the cornea relative to the scanning deviceduring the LASIK treatment.

The scanning device can be used with any sources of optical radiation,however showing preferably a femtosecond laser for the emission offemtosecond pulses along the luminous beam, whereby the laser which islaid over the entrance optics and the focusing optics of the focusedluminous beam in the focus has a diameter smaller than 5 μm. Suchscanning device is suitable in particular for the very precisepreparation of the cornea cover during a LASIK treatment. However, thescanning device can also be used for other purposes. Preferably a laserscanning microscope with a laser for emitting illumination laserradiation over a scanning device designed according to the invention forfocusing the illumination laser radiation. The laser scanning microscopecan have in particular control equipment, which is lead into thescanning device in such a way that the focus of the lighting laserradiation scans laterally and is directed into the depth by a givenscanning volume. Preferably thereby a specimen holder of the laserscanning microscope and the focusing optics are at least arranged forscanning a sample fixed to each other. Such a laser scanning microscopehas the advantage that it is not necessary to move the specimen tablefor moving the sample, which on one hand simplifies the structuresubstantially and on the other hand allows a faster adjustment of thefocus position in the z-direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described below in more detail using the drawings. Theyshow:

FIG. 1 a schematic and simplified representation of a system forlaser-surgical eye treatment with a scanning device designed accordingto an embodiment of the invention,

FIG. 2 a schematic partial representation of a laser-surgical treatmentsystem designed according to an embodiment of the invention,

FIG. 3 a schematic representation of a system for the laser-surgicaltreatment of the eye with a scanning device designed according to anembodiment of the invention, and

FIG. 4 a schematic representation of a laser scanning microscopedesigned according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a laser-surgical system for the treatment of a human eye 1with a radiation source 2 in the form of a femtosecond laser for theemission of a pulsed laser radiation in the form of a pulsed luminousbeam 3 and a scanning device 4 designed according to an embodiment ofthe invention, by means of which the luminous beam 3 can be focused intodifferent, given ranges in a three-dimensional volume in the cornea ofeye 1. On the cornea of eye 1 is a contact lens 5 with a concave contactarea, against which rests the cornea of eye 1, whereby any movement ofthe cornea is suppressed during a treatment with laser radiation as muchas possible.

The radiation source 2 in the form of a femtosecond laser is adjustedand actually prepared for the delivery of femtosecond pulses with awavelength in a range of approx. 1040 Nm with a pulse width within therange of approximately 200 fs. It can in particular include pulseforming mechanisms beside the actual laser.

The scanning device 4 adjusts the direction of the luminous beam 3 overthe entrance optics 6, by which the luminous beam 3 enters the scanningdevice 4, a deflecting device 7, the luminous beams 3 emitted from thelaser from the entrance optics 6 corresponding to the given controlsignals in lateral direction, this is transverse to the direction of theluminous beams deflected from the deflecting device 7, and focusingoptics 8 firmly arranged relative to the deflecting device 7, forfocusing the luminous beam 3 emitted from the entrance optics 6 anddiverted by the deflecting device 7, which focuses it in the region ofthe cornea of eye 1. The deflecting device schematically shown 7 isadjusted in an actually known way and is regulated by two reflectiveelements 9 and 9′ in the form of mirrors for the emission of theluminous beam 3, which can be tilted and supported on the axles notshown in FIG. 1. For a simpler representation, the reflective elements 9and 9′ are only shown parallel to each other in a schematic way, howeverthe tilting axles run perpendicularly to each other and into a Z-axis ofthe entrance optics 6 in FIG. 1, so that by tilting the first reflectiveelement 9 of luminous beam 3 in the Y-direction, this is in FIG. 1upwards or downwards, and by tilting the second reflective element 9′ inthe Y-direction and the optical axis of the entrance opticsperpendicularly in the X-direction, in FIG. 1 and/or from the indicationlevel, can be diverted. The reflective elements and/or mirrors 9 and 9′are galvanometrically linked, whereby actuators 10 and/or 10′ areintended to be connected with the control equipment in FIG. 1 by arrowsthat indicate signal connections. The control equipment givescorrespondingly the desired focus position of luminous beam 3 in thelateral direction, this is in the x and y directions from the controlsignals from actuators 10 and 10′, on which the reflective elementsand/or mirrors 9 and 9′ are tilted in a well-known way.

The entrance optics 6 is regulated over a movable optical elementrelative to the deflecting device 7 in the form of a first lens 11 withnegative refraction power; this is a diverging lens, as first opticalelement as well as a collecting lens 12 which has positive refractionpower. The Z-axis of these two lenses runs coaxially. The first lens 11is placed in a lens holder 13, which is adjustable in a linear guide notshown in FIG. 1 in a parallel direction to the Z-axis of first lens 11,so that first lens 11 is an optical element of entrance optics 6 thatcan move relative to the deflecting device 7. The actuator only shownschematically in FIG. 1 serves for the movement of lens holder 13 andalso to the first lens 11 parallel to their Z-axis, for example a lineardrive 14 which is again indicated by an arrow, with which is connectedto control equipment (not shown). This sends control signals to thelinear drive 14 for the movement of the first lens 11 depending on thedesired focus position along the direction of the luminous beam 3 withinthe range of the focus control signal. In this example, linear drive 14is a stepper linear motor.

In a position of the movable optical element shown in FIG. 1 relative tothe deflecting device 7 through lines drawn from first lens 11 to thecollecting lens 12, the entrance optics 6 works as an expander thatincreases the cross section of luminous beam 3, whereby the parallelluminous beam 3 before the entrance optics 6 is made parallel again bythese emitted luminous beam 3.

Focusing optics 8 is represented in FIG. 1 of this application exampleonly as an stationary emission lens 15 relative to the deflecting device7 and/or the objective lens in form of a collecting lens, which focusesthe luminous beam 3 emitted from entrance optics 6 and diverted bydeflecting device 7 in the lateral direction into the cornea region ofeye 1. The emission lens 15 is however only a schematic representationof an optical system of positive refraction power, which may be morecomplex, and whereby this structure does not play a role in the contextof this representation.

Focus position F of luminous beam 3 in the direction along the luminousbeam is determined by entrance optics 6 and focusing optics 8. Focusposition F in the direction of the luminous beam is adjusted by movingthe first lens 11 along its Z-axis relative to deflecting device 7 andfocusing optics 8. In case of a change of the distance between firstlens 11 and collecting lens 12, the divergence of luminous beam 3parallel to lens 11 is changed, which is clearly represented by thebroken lines in FIG. 1. Depending on the position of the first lens 11,the luminous beams emitted from collecting lens 12 can be made parallelor convergent. Depending on the divergence, the fixed optics 8 focusesthen the luminous beam into different distances from focusing optics 8and/or the emitting lens 15.

In the following example, the first lens 11 can be moved very fast andsimply, since with a diameter of approx. 6 mm it is small and light.Beyond that, the speed ratio of the movable optical element relative todeflecting device 7, this is the first lens 11, in a correspondingmotion of focus F in the direction of luminous beam 3, in this exampleis for instance 20:1, which is substantially larger than the one used onthe subordinate zoom optics of the deflecting device, with whichtypically a clearly smaller speed ratio can be expected. For example, inUS 2003/0053219 A1 it has a value of 1:1.

FIG. 2 shows a laser-surgical system with a scanning device designedaccording to another embodiment of the invention. This scanning devicediffers from the first scanning device 4 as the path of rays betweendeflecting device 7 and focusing optics 8 is arranged with thecollecting lens working as emission lens 15 and a beam splitter 16, bymeans of the outgoing observation luminous beams 17 from points in thecornea of eye 1, which approach infinity during the illustration ofobject points in the cornea of eye 1 by emitting lens 15, from the pathof rays between deflecting device 7 and focusing optics 8 in thedirection of a tube with eyepiece, not shown in the figures, or anobjective with camera, not shown in the figures either, which can be atleast partly diverted, so that it is possible to monitor the corneaduring the emission of luminous beam 3 on that cornea. Therefore atleast during the treatment duration, the focusing optics 8 and thecornea of eye 1 must keep a fixed relative distance between each otherand the focal point of focusing optics 8 lies in the working volume,monitoring then also takes place with constant sharpness, if the focusof luminous beam 3 is moved into the depth, this is in a directionparallel to the direction of luminous beam 3 in the proximity of thefocus. During the definition of the observation aperture, it ispreferably considered that on one hand a sufficiently bright picturewith good resolution and on the other hand a depth of field as large aspossible can be achieved.

FIG. 3 shows partially and schematically a laser-surgical system with ascanning device 4′ designed according to an embodiment of the invention.Those components which comply with the components of the firstapplication example are designated with the same reference symbols andthe applications in the first application example also apply hereaccordingly to these components.

The deflecting device 7 is replaced here by a deflecting device 7′,which only differs from the deflecting device 7 by the distance ofreflective elements 9 and 9′ between each other. The tilting axle ofreflective element 9 runs perpendicular to luminous beam 3 and cuts atleast approximately the Z-axis of entrance optics 6. Thiscorrespondingly applies to reflective element 9′ and focusing optics 8′.In the rest position, reflective elements 9 and 9′ are aligned to eachother in such a way that the incoming beam along the Z-axis of entranceoptics 6 within the area of the tilting axle of the second reflectiveelement 9′ comes out through these. In the rest position, the mirrorsare bent opposite the Z-axis of entrance optics 6 and/or focusing optics8′, for instance in an angle of 45°.

Beyond that, a pupil optics set 18 is arranged in the path of raysbetween reflective elements 9 and 9′, which includes two collectinglenses 19 and 19′, which image the luminous beam 3 emitted that firstreaches reflective element 9 on the other reflective element 9′, wherebya real intermediate image is formed in space, between the collectinglenses 19 and 19′, in order to avoid optical openings in the componentsof the scanning device. In this way a fixed position of the pupil isachieved which facilitates a favorable implementation of focusing optics8′. By the construction of reflective elements 9 and 9′ into each other,the size of reflective element 9′ can be kept small, as in the examplethe mirrors are shaped as ellipses, whose main and/or secondary axishave a length of approximately 21 mm and/or 15 mm.

Focusing optics 8′ differs from the focusing optics 8 in severalaspects. It is made out of multiple parts and has an entrance objective20, which emits a luminous beam 3 which is laterally diverted fromdeflecting device 7′ and a real intermediate image is focused on aTubular lens 21, which shows the intermediate image depending on itsposition into infinity, a beam splitter 16′ following tubular lens 21,which diverts the luminous beam 3 on the emission lens 15′, and theemission lens 15′ in which luminous beam 3 is here parallel or onlyweakly convergent or weakly divergent, then is focused depending on itsfixed focal length on the cornea of eye 1 and thus functions as anobjective lens.

The adjustment of the focus position in the lateral direction and in thedirection of luminous beam 3 near the focus takes place as in the firstapplication example.

The beam splitter 16′ is adjusted in such a way that the observationluminous beams 17′, which results from the points in the cornea of eye 1imaged by emission lens 15′ to infinity, by which beam splitters 16′ arepassed through a tube with an eyepiece not shown in FIG. 3, or throughan objective with a camera, not shown in FIG. 3, can be supplied. As itis shown in the second application example, this makes it possible tomonitor with the luminous beam 3 during a LASIK treatment.

The dismantling of the focusing optics in the entrance objective 20, inthe tubular lens 21 and the emission lens 15′ and/or the main objectivehas the advantage, asides from the possibility of making an interfacepossible for monitoring so that small beam diameters can be achieved atthe entrance of the focusing optics. For example, the beam diameter canreach up to 15 mm, so that the reflective elements 9 and 9′ can be usedwith a work diameter of 15 mm. This relatively small size of thereflective elements 9 and 9′ is favorable for the achievement of highscanning speeds. Beyond that, the dismantling into subsystems makespossible a limited diffraction correction of the focusing optics for thefocusing optics. Since the beams between the subsystems do not have tobe corrected, compensation effects can be used, which clearly reduce thenumber of necessary lenses.

In order to avoid undesired reciprocal effects, all optical componentsare laid out in such a way in this as well as in all other applicationvariations, that all real intermediate pictures are formed in the airand so also very intensive laser radiations cannot be directed towardsthe optical openings in the optical components. The application examplesdescribed here are in each case an entire optical system of the scanningdevice, in particular the initial and focusing optics, for which thespectral width is chromatically corrected by using a femtosecond pulse.Pulse duration can be obtained by an adapted dispersion managementbefore the pulse enters the system and the already mentioned chromaticcorrection of the entire optical system, whose focus dispersion is dueto chromatic aberrations, lies less than 30% above the theoreticallyattainable pulse duration.

The movable optical element is movable over a distance relative to thedeflecting device sufficiently large that the focus of the luminous beamcan be moved in the beam direction over a range larger than about 0.5millimeter. The deflecting device is further adjusted in such a way thatthe focus of the luminous beam can be moved in a lateral range which hasa diameter of 11 mm.

The laser, the entrance optics and the focusing optics are laid out insuch a way that the focused luminous beam in the focus has a diametersmaller than 5 micrometers. The focusing optics in the applicationexample preferably has an opening larger than0.35.

These laser-surgical systems are therefore suitable in particular forthe formation of a hinged cornea flap by photo disruption by means offemtosecond pulses.

FIG. 4 shows a laser scanning microscope with a scanning device designedaccording to an embodiment of the invention.

From a radiation source 22, in the example a laser, a lighting luminousbeam 3″ is emitted, which arrives to a beam splitter 23 and then is leadinto a scanning device 4″, which is in principle built similar to thescanning device 4 of the first application example. However thedimensions of the used components on the application are adapted to alaser scanning microscope.

Scanning device 4″ includes again an entrance optics 6″, which changesthe divergence of radiation beam 3″ emitted from beam splitter 23depending in the control signals received from the control equipment ofthe laser scanning microscope, not shown in FIG. 4, and a deflectingdevice 7″, which diverts radiation beam 3″ emitted from entrance optics6″ and which is laterally diverted depending on the control signals ofthe control equipment of the laser scanning microscope, and a firmlyarranged focusing optics 8″ relative to radiation beam 3″ diverted bydeflecting device 7″, focused on the examined sample 24. The layout ofthe optical elements and the distances of entrance optics 6″, deflectingdevice 7″ and focusing optics 8″ correspond to entrance optics 6,deflecting device 7 and focusing optics 8, so that the same referencesymbols are used in FIG. 4 for these components and the explanations ofthese also apply accordingly here.

The radiation coming from sample 24 is focused again by focusing optics8″ and after passing deflecting device 7″, entrance optics 6″, as wellas after being diverted by beam splitter 23, by collecting optics 25.The focus is blended with the focus of luminous beam 3″ in sample 24. Afine aperture and/or pinhole screen 26 serves in a well-known way fordepth discrimination, essentially by only letting through light from thefocus of luminous beam 3″. The optical radiation that passes throughpinhole screen 26 is detected by a detection mechanism 27.

In order to generate an image, the control equipment not shown in thefigures proceeds to rastering the focus of luminous beam 3″ bothtransversally to the direction of luminous beam 3″ and parallel to wherethe detected positions signals of the detection mechanism 27 arecollected in each case. In addition, it delivers the appropriate controlsignals to deflecting device 7″ and to linear drive 14 for the desiredfocus position in each case.

The size of the optical element which can be moved can also be kept heresmall and light with an appropriate adjustment of lens 11, so that afast movement of the focus of luminous beam 3 relative to sample 24 canbe achieved, so that the sample table on which sample 24 is held andwhich is not shown on FIG. 4 need not be moved.

A further application example differs from the second applicationexample by adjusting the entrance optics. The lenses and/or groups oflenses are replaced here by diffractive optical elements. The entranceoptics includes first and second diffractive optical elements. The firstdiffractive optical element is adjusted and arranged in such a way thatit transforms a parallel beam in a basic position into a convergentbeam. The second diffractive optic element following in the path of raysis adjusted and arranged in such a way that it again transfers theconvergent beam into a parallel beam. All of this results altogetherinto an expansion of the beam. The distance between the first and seconddiffractive optical elements is modified for changing the divergence ofthe beam emitted from the entrance optics.

In another application example, the entrance optics of the precedingapplication example is changed in such a way that the entrance opticspossesses now two concave mirrors, which are arranged in such a way thatthe distance between the laser and the deflecting device are doubled,resulting in an approach to the z-shaped path of rays. The first concavemirror produces a real intermediate image, which shows a subordinatesuitable basic distance from the first concave mirror to the secondconcave mirror in the path of rays into infinity. The divergence issteered by changing the distance between the hollow mirrors. The focallength ratio determines the relationship between the diameter and/or theopening angles of the beam emitted from the entrance optics and thediameter and/or the opening angles of the incoming beam to the entranceoptics.

Reference symbol list 1 Eye 2 Radiation source 3 3′ Radiation beam 4 4′4″ Scanning device 5 Contact glass 6 6′ Entrance optics 7 7′ 7″Deflecting device 8 8′ 8″ Focusing optics 9 9′ Reflective elements 1010′ Actuators 11 First lens 12 Collecting lens 13 Lens holder 14 Lineardrive 15 15′ Emission lens 16 16′ Beam splitter 17 17′ Observationluminous beam 18 Pupil optics 19 19′ Collecting lenses 20 Entranceobjective 21 Tubular lens 22 Radiation source 23 Beam splitter 24 Sample25 Collecting optics 26 Pinhole screen 27 Detection device

1. (canceled)
 2. A surgical laser system including a scanning device forfocusing a luminous beam into a selected range of an eye to be treated,the surgical laser system comprising: a femtosecond surgical lasersource that produces the luminous beam, the femtosecond surgical lasersource being structured to produce photodisruptions within tissues ofthe eye to be treated upon focal application of the luminous beam to thetissues; entrance optics following the femtosecond surgical laser sourceinto which the luminous beam first enters comprising at least a firstoptical element; focusing optics by which the luminous beam emitted fromthe entrance optics is focused on or into the eye to be treated; adeflecting device arranged between the first optical element and thefocusing optics that diverts a focus position of the luminous beam; thedeflecting device comprising a first movable reflective element movableabout a first axis configured to deflect the luminous beam in an Xdirection and a second movable reflective element movable about a secondaxis that is substantially orthogonal to the first axis configured todeflect the luminous beam in a Y direction; a beam splitter, locatedbetween the deflecting device and the focusing optics; and in which theentrance optics and focusing optics are chromatically corrected over aspectral range of selected femtosecond pulses.
 3. The surgical lasersystem including a scanning device as claimed in claim 2, the entranceoptics comprising at least one movable optical element that isconfigured to be movable along an axis generally parallel to theluminous beam where the luminous beam passes through the entrance opticsto the deflecting device to adjust the focus position of the luminousbeam within a portion of the eye.
 4. The surgical laser system includinga scanning device as claimed in claim 2, further comprising a contactlens following the deflecting device and the focusing optics that isengageable with a cornea of the eye, the contact lens having a contactarea by which contact with the cornea is made.
 5. The surgical lasersystem including a scanning device as claimed in claim 3, furthercomprising at least one movable optical element, which when displacedrelative to the deflecting device, alters the divergence of theradiation beam emitted from the entrance optics.
 6. The surgical lasersystem including a scanning device as claimed in claim 2, in which thefirst optical element of the entrance optics comprises a lens or a groupof lenses with negative refractive power and the surgical laser systemfurther comprising a collecting lens or group of lenses with positiverefractive power arranged in the direction of the luminous beam.
 7. Thesurgical laser system including a scanning device as claimed in claim 2,in which the first optical element of the entrance optics comprises anon-planar mirror.
 8. The surgical laser system including a scanningdevice as claimed in claim 3, in which the movable optical elementcomprises the first optical element and the movable optical element hasa negative refraction power lens or comprises a group of lenses havingnegative refractive power.
 9. The surgical laser system including ascanning device as claimed in claim 3, in which the movable opticalelement comprises a diffractive optical element.
 10. The surgical lasersystem including a scanning device as claimed in claim 3, in which themovable optical element comprises a reflective optical element.
 11. Thesurgical laser system including a scanning device as claimed in claim 3,further comprising a driving device which moves the movable opticalelement relative to the deflecting device.
 12. The surgical laser systemincluding a scanning device as claimed in claim 11, in which the drivingdevice comprises a linear drive.
 13. The surgical laser system includinga scanning device as claimed in claim 2, in which the deflecting deviceis positioned between the entrance optics and the focusing optics. 14.The surgical laser system including a scanning device as claimed inclaim 13, further comprising pupil optics, and a collecting lens whichis arranged between the first movable reflective element and the secondmovable reflective element, and in which the first movable reflectiveelement is imaged on the second movable reflective element.
 15. Thesurgical laser system including a scanning device as claimed in claim 2,in which the focusing optics have a fixed focal length.
 16. The surgicallaser system including a scanning device as claimed in claim 2, whereinthe focusing optics further comprises an emission lens or an emissionlens group and wherein the beam splitter is positioned in the path ofrays between the deflecting device and the emission lens or the group ofemission lenses of the focusing optics.
 17. The surgical laser systemincluding a scanning device as claimed in claim 16, in which theemission lens or the emission lens group focuses a substantiallyparallel luminous beam into the given volume.
 18. The surgical lasersystem including a scanning device as claimed in claim 2, in which thefocusing optics creates a real intermediate image through an entranceobjective, produced by the luminous beam emitted from a radiationsource.
 19. The surgical laser system including a scanning device asclaimed in claim 2, in which all real intermediate images produced bythe luminous beam emitted by the femtosecond surgical laser source areformed in gas, air or vacuum.
 20. The surgical laser system including ascanning device as claimed in claim 3, in which the movable opticalelement is movable over a distance relative to the deflecting devicesufficiently large that the focus of the luminous beam can be moved inthe beam direction over a range larger than about 0.5 millimeter. 21.The surgical laser system including a scanning device as claimed inclaim 2, in which the deflecting device is operable such that the focusof the luminous beam can be moved laterally in a range having a diameterof at least about eleven millimeters.
 22. The surgical laser systemincluding a scanning device as claimed in claim 2, wherein thefemtosecond laser radiation source, the entrance optics and the focusingoptics are configured such that the focus of the luminous beam has adiameter smaller than about five micrometers.
 23. A method of focusing aluminous beam into a selected range of a volume of an eye to be treated,the method comprising: producing the luminous beam with a femtosecondlaser source and structuring the luminous beam to producephotodisruptions within tissues of the eye to be treated upon focalapplication of the luminous beam to the tissues; directing the luminousbeam into entrance optics comprising at least a first optical element;deflecting the luminous beam about a first axis and second axis that isorthogonal to the first axis; dividing the luminous beam with a beamsplitter; then focusing the luminous beam on or into the eye to betreated with focusing optics; and utilizing chromatically correctedoptics that are chromatically corrected over a spectral range ofselected femtosecond pulses for the entrance optics and the focusingoptics.
 24. The method of focusing a luminous beam into a selected rangeof a volume of an eye to be treated as claimed in claim 23, furthercomprising moving a movable optical element of the entrance optics alongan axis parallel to the luminous beam to adjust the focus position ofthe luminous beam within a portion of the eye.
 25. The method offocusing a luminous beam into a selected range of a volume of an eye tobe treated as claimed in claim 23, further comprising applying a contactlens to a cornea of the eye and directing the luminous beam through thecontact lens.
 26. The method of focusing a luminous beam into a selectedrange of a volume of an eye to be treated as claimed in claim 23,further comprising altering the divergence of the radiation beam emittedfrom the entrance optics by movement of a movable optical element. 27.The method of focusing a luminous beam into a selected range of a volumeof an eye to be treated as claimed in claim 24, further comprisingmoving the movable optical element by operation of a driving device. 28.The method of focusing a luminous beam into a selected range of a volumeof an eye to be treated as claimed in claim 23, further comprisingcollecting light at a collecting lens which is arranged between a firstmovable reflective element and a second movable reflective element thatdeflect the luminous beam about the first axis and the second axis. 29.The method of focusing a luminous beam into a selected range of a volumeof an eye to be treated as claimed in claim 28, further comprisingimaging the first movable reflective element on the second movablereflective element.
 30. The method of focusing a luminous beam into aselected range of a volume of an eye to be treated as claimed in claim23, further comprising forming all real intermediate images produced bythe luminous beam in gas, air or vacuum.
 31. The method of focusing aluminous beam into a selected range of a volume of an eye to be treatedas claimed in claim 24, further comprising moving the movable opticalelement over a distance relative to the deflecting device sufficientlylarge that the focus of the luminous beam is moved over a range largerthan 0.5 millimeter.
 32. The method of focusing a luminous beam into aselected range of a volume of an eye to be treated as claimed in claim23, further comprising deflecting the luminous beam laterally in a rangehaving a diameter of at least eleven millimeters.
 33. The method offocusing a luminous beam into a selected range of a volume of an eye tobe treated as claimed in claim 23, further comprising focusing theluminous beam such that the focus of the luminous beam has a diametersmaller than five micrometers.